I'm not really sure to what degree this is a statistical question but thought this might be the best place to start. If my questions prove only my ignorance please vote it down and I'll delete the thread hopefully making more accurate google searches in the future

Greetings,

could anyone please explain why there is no (to my knowledge) concise description (agreement) on how to compute power and sample size for a planned experiment involving factorial repeated measures?

In my field (psychology) balanced repeated measures designs are very common. With the replicability crisis going on, preregistering experiments and establishing a desired sample size beforehand is considered best practice. Also, reviewers seem to ask for power "numbers" (whatever it mean).

How to calculate the sample size upfront in context of purely repeated measures designs (varying from two level A * B setups to four level A * B * C * D setups, where complex fixed effects interactions are of interest)

How to reply reviewers when for some reasons one could not (or didn't know how) compute power or desired sample size before running the experiment

How to approach replication scenarios when one knows effect sizes for a published experiment and based on that would like to plan a powerful replication.